Direct Aortic Access for TAVI Shows Promise

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These studies were published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

These two studies evaluated the safety and effectiveness of a direct aortic approach for transcatheter aortic valve implantation in patients in whom vascular access through femoral or subclavian arteries is not possible, typically due to vascular disease.

Preliminary results suggest that the approach is feasible and safe.

FT. LAUDERDALE -- A minimally invasive surgical approach to transcatheter aortic valve implantation (TAVI) that goes directly through the aorta is associated with low rates of mortality and complications, according to two late-breaking clinical trial presentations here.

In one study that used the Sapien valve (Edwards Lifesciences), the transaortic approach in 158 patients resulted in no postoperative strokes, a 30-day all-cause mortality rate of 7%, and a major bleeding rate of 1.3%, reported Vinnie N. Bapat, MBBS, MS, from Guy's and St. Thomas' Hospital NHS Trust in London, at the Society of Thoracic Surgeons meeting.

In another study, which used the CoreValve (Medtronic) prosthesis, the direct aortic approach in 93 patients resulted in an inhospital major stroke rate of 3.2%, 30-day mortality rate of 9.7%, and a major bleeding rate of 4.3%, according to Neil Moat, MBBS, from the Royal Brompton Hospital in London. (The Sapien valve is FDA approved, while the CoreValve is not.)

For comparison, in the PARTNER trial cohort A (high-risk patients randomized to TAVI [n=348] or surgery [n=351]), the 30-day major stroke rate for TAVI was 3.8%, for mortality 3.4%, and for major bleeding 9.3%.

Bapat noted that the initial protocol at his facility was to attempt the transfemoral approach first and if that was not possible, try transapical and then transaortic. But now, if a patient is not suitable for the transfemoral approach, they immediately go for transaortic access.

But several attendees wanted to know why the transaortic approach was not the first choice, given its excellent outcomes.

Bapat said it might be difficult to "sell" the transaortic approach to patients because it involves a 5-cm incision in the chest, either via a mini-sternotomy or a mini-thoracotomy, as opposed to a short incision at the groin.

But attendees would not be appeased. Several said that patients would be swayed by the excellent "hard" endpoints. "The incision will be forgotten in four weeks. What's important is the low risk of stroke," said one session attendee.

It also was noted that no data exist from randomized clinical trials showing that one approach is better than the other, so transfemoral access need not be the default approach.

In the study headed by Bapat, researchers retrospectively examined data from 158 patients (out of a total of 1,236 in the European Multicenter Experience) who underwent TAVI with the Sapien valve using the transaortic approach. All of those patients were not suitable for the transfemoral approach.

The mean age was 80, and 61% were women. Nearly 40% had peripheral vascular disease, one-quarter had diabetes, 13% had previous coronary artery bypass grafting (CABG), 37% had chronic obstructive pulmonary disease, 35% had an ejection fraction less than 50%, and the mean Euroscore was 32 -- indicating a significant preoperative risk of mortality with standard surgery.

Nearly all the cases (138) were done via a mini-sternotomy, and six had a full sternotomy.

One case did not have procedural success. All cases had only one valve deployed and all cases underwent preplanning using CT scans, which both Bapat and Moat said is essential in all TAVI cases.

In particular, CT scans can help with the following:

Determine if the aortic access site is ≥6 cm from the annulus

Assess location of the ascending aorta

Select access site to achieve a delivery trajectory that optimizes coaxial alignment with native aortic valve

In the study headed by Moat, researchers retrospectively examined data from 93 patients having the CoreValve implanted directly through the aorta. Researchers had asked all European centers with at least three transaortic cases to contribute procedural data and outcomes.

The mean age was 80 and slightly more than half (53%) were men. More than 80% were NYHA class III and IV, 60% had coronary artery disease, one-quarter had prior CABG, 83% had peripheral arterial disease, and the mean Euroscore was 28 -- again indicating a significant risk with standard surgery.

Approximately half of the patients received the replacement valve through a mini-thoracotomy and half through a mini-sternotomy.

Interestingly, 21% of the transaortic cases took place in the 54 months after the first implant in 2008, and 79% took place in 2011. Moat and colleagues found a 15% mortality rate in the early cases versus 8.2% in the later cases. In addition, those institutions that performed three or fewer cases had a 14% mortality rate compared with a 7% rate for those who performed more than three cases.

"The key is careful patient selection that should be done with a multidisciplinary team," Moat told MedPage Today. In his facility, operators will attempt transfemoral access first, then subclavian, and then transaortic.

One of the advantages of the transaortic approach is the ease with which to potentially place an embolic filter for protection, Moat said, although he and colleagues do not currently include such embolic protection.

Both Moat and Bapat emphasized the excellent control of the catheter when the operator achieves a "very coaxial approach with the valve," Moat told MedPage Today. "If you move 1 mm, the valve moves 1 mm. The control is extremely high."

Both studies were limited by their retrospective nature and small numbers.

The direct aortic approach also is being evaluated in the Medtronic CoreValve U.S. Pivotal Trial.

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